A typical power cable includes one or more conductors in a cable core surrounded by one or more layers of polymeric material. Medium voltage (6 to 36 kV) and high voltage (greater than 36 kV) and extra high voltage (greater than 220 kV) cable typically include a core surrounded by an inner semiconducting layer, followed by an insulating layer, and then an outer semiconducting layer, and an outermost layer (or sheath).
The load-carrying capacity of a cable system is limited, in part, by the heat transfer away from the conductor. Polyolefins, such as polyethylene, are frequently utilized in the insulating layer and/or in the semiconducting layer. Polyethylene has a low dielectric permittivity and a relatively high electrical breakdown strength.
Known are voltage stabilizing agents for polyolefin compositions that increase electrical breakdown strength of insulating layers in power cable. Conventional voltage stabilizing agents (such as the family of polycyclic aromatics, e.g. acenes), however, have poor compatibility with polyolefins. The art recognizes the continuous need for voltage stabilizing agents compatible with polyolefins for (i) increased electrical breakdown strength of cable insulation material, (ii) increased reliability with existing cable designs and/or (iii) provision of high-stress designs that are able to deliver increased amounts of energy.